1. Field of the Invention
The present invention relates to a structure for grounding a photoreceptor web installed at a liquid electrophotographic printer. The present application is based on Korean Patent Application No. 99-26341, which is incorporated herein by reference.
2. Description of the Related Art
A liquid electrophotographic printer such as a color laser printer, as shown in FIG. 1, includes a photoreceptor web 10, which circulates while being supported by a plurality of rollers 11, 12 and 13 installed at a belt unit in the printer. A predetermined electrostatic latent image is formed on one side of the photoreceptor web 10 by a laser scanner 16. The electrostatic latent image is developed into a colored image by a development unit 17. The developed image is dried as it passes a drying unit 14 and printed on a sheet of paper 1 at a transfer unit 15. Reference numerals 18 and 19 denote a charging device and a topping corona for applying a predetermined voltage to the photoreceptor web 10 for formation and removal of the electrostatic latent image, respectively. That is, the photoreceptor web 10 is charged to a high voltage by the topping corona 19 and a voltage of only a portion of the photoreceptor web 10 scanned by the laser scanner 16 drops. Thus, the electrostatic latent image is formed on the photoreceptor web 10 due to the difference in electric potential. After the image developed while passing the development unit 15 is printed on the paper 1, the image is charged by the charging device 18 and the voltage of the image formed on the photoreceptor web 10 changes to a normal state so that the electrostatic latent image is removed.
In order to charge the photoreceptor web 10 to a predetermined electric potential and maintain the electric potential, at least a portion of the photoreceptor web 10 must be grounded. That is, the grounded state enables maintenance of a relative voltage value.
According to the conventional technology, a grounding brush 20 fixed to a main frame (not shown) is provided so that one side of the photoreceptor web 10 is in contact with the grounding brush 20 when circulating. That is, the photoreceptor web 10 is grounded via the grounding brush 20 and the main frame.
However, as the photoreceptor web 10 is repeatedly contaminated with developer adhering thereto while printing, the grounding brush 20 contacting the photoreceptor web 10 gradually becomes contaminated with the developer. As the contamination becomes significant, the grounding brush 20 may lose its grounding effectiveness. When the contamination becomes serious, the grounding brush 20 is preferably replaced by a new one. However, as the grounding brush 20 is fixed at the main frame in the printer of the conventional structure, the procedure of disassembling and installing the grounding brush 20 to replace it is difficult as one must manually do these jobs while fitting one's hands through a narrow space of the printer, or alternatively, the printer itself must be disassembled. Hence, a structure that allows for the easy replacement of the grounding brush 20 is desired.